In recent years, systems for displaying images using augmented reality (AR) technology have been widespread (see, for example, Japanese Laid-open Patent Publication No. 2015-118641). In one example of the AR technology, an object is photographed using a camera mounted on a personal computer (PC), a mobile terminal device, or the like, and the position and the orientation of the camera in the three-dimensional space are estimated from the image of the object. Content information is superimposed and displayed at any position in the image based on the determined position and the orientation of the camera.
From the image of the object, various techniques for estimating the relative position and the relative orientation between the object and the camera are known (see, for example, Japanese Laid-open Patent Publication No. 2007-333679, Japanese Laid-open Patent Publication No. 2015-7639, and Japanese Laid-open Patent Publication No. 2016-170050). Techniques such as a camera calibration, a line segment detection, a three-dimensional machine perception, a orientation estimation by straight line association, a polyhedral representation for computer vision, and so forth are also known. As a related art, disclosed are, for example, Japanese Laid-open Patent Publication No. 2015-118641, Japanese Laid-open Patent Publication No. 2007-333679, Japanese Laid-open Patent Publication No. 2015-7639, and Japanese Laid-open Patent Publication No. 2016-170050.
In a case where the position and the orientation of the camera are estimated by associating an image of an object photographed by a camera with computer-aided design (CAD) data representing the three-dimensional shape of the object are associated with each other, the amount of calculation for the association increases.
Such a problem is not limited to the case of associating the image of the object with the CAD data but also in the case of associating the image of the object with other shape information.
In view of the above, it is desirable to reduce the amount of calculation for associating the image of the object with the shape information representing the shape of the object when estimating the position and the orientation of the imaging device.